Highlighting this point is a study of college football players preparing for a major NFL scouting event by trainer Amanda Carlson. She found that 98 percent of them were dehydrated at the morning evaluation.

Another study by researchers at Tufts University found that college athletes who were mildly dehydrated and engaged in high-impact aerobics for 60 to 75 minutes without adequate water intake were more likely to feel fatigued, confused, angry, depressed or tense.

The point? No matter if you're an elite athlete, a weekend warrior or a gym rat, water matters.

"In my experience, most people are not aware of how much they're drinking and are not drinking enough -- many, as little as half of what they need," says Carlson, director of performance nutrition at Athlete's Performance, a training facility for world-class athletes.

Not only does water help your workout performance, but also can help control those pesky (unwanted) pounds.

"Water's involved in every type of cellular process in your body, and when your dehydrated, they all run less efficiently -- and that includes your metabolism," says Carlson.

Additionally, it's difficult for the body to distinguish between hunger and thirst. So quite often, when you feel hunger, it may just be your body needing a drink.

But not all water is the same. Some has benefits that tap and other bottled waters simply do not.

Think of it this way: in order for your body to function properly, it must continuously work to maintain a proper pH, or chemical balance. An unbalanced pH can force your body to borrow important minerals from your vital organs and bones in order to remove excess acid, according to Dr. Theodore A. Baroody. By using a mildly alkaline water you have a better chance of pre-empting sickness, premature aging, weak bones and fatigue.

Another benefit of drinking alkaline water is that it is infused with high levels of stabilized, dissolved oxygen, which is not only good for overall health, but improves aerobic capacity and enhances energy and overall vitality.